1. Field of the Invention
The present invention relates to a method for reading sensor. More particularly, the present invention relates to a method for reading sensor that stores data in numerous memory cells that are independent from each others.
2. Description of the Prior Art
A variety of sensors have been applied popularly in modern industry and manufactures, such as image sensors, alcohol sensors, photoelectric switches and the like. Generally, except sensors only for detecting the existence of objects, all sensors for sensing contents of objects comprise a plurality of sensing units for sensing and a plurality of memory cells for storing the sensed data. Of course, sensing units and memory cells can be separated; or initially combining one sensing unit and one memory cell as a basic unit, and then combine a plurality of basic units to be a whole sensor.
In prior arts, all sensed data are stored in memory cells. Thus, the way for reading sensor is to read the contents of all cells from the first one. Referring to FIG. 1A, initially prepare the sensor 10 with M memory cells 11; then use sensor 10 to sense a certain object to make each memory cell 11 store a data (data1, data2, . . . data M); finally one by one read out the data composed of data1, data2, . . . until data M. For instance, use shift register to record charge movement within all basic units of a image sensor by using CCD (charge-coupled device), wherein read restored data in each basic unit sequentially from the first one.
However, considering somewhat application of sensors, frequently only parts of memory cells stores non-zero signals and users may need (or interest in) some parts of sensed contents rather than the whole one during sensing the content of a certain object. Thus the prior art is usually inefficient.
Referring to FIG. 1B and FIG. 1C, for example, considering photoelectric sensor 15 in the scanning head 14 of a scanner, the length of the object 16 parallel with the photoelectric sensor 15, waiting for being scanned, is possibly smaller than the length of the photoelectric sensor 15. A user may interest in a certain part of image (172) of the object rather than the whole image (171, 172, 173). Thus, in the prior arts, it is obviously not efficient that the user must read the whole data in the photoelectric sensor 15 to acquire and to deal with demanded partial data.
Therefore, it is necessary to develop a new method for reading sensor to let the user more efficiently read demanded data.